Field of the Invention
This invention relates to the support or suspension of an electrically driven diaphragm of an acoustical loudspeaker.
It is generally known that the support of the sound radiating diaphragm of an acoustical speaker affects the quality or distortion of the sound being reproduced from an electrical driving signal usually applied through an amplifier to a voice coil fixed to the diaphragm and positioned within a magnetic circuit. In an effort to reduce distortion, various diaphragm supporting arrangements and suspension means have been proposed including pressurized air support, electrostatic devices and energy absorbing devices. Diaphragm supporting arrangements for such purposes are disclosed for example in U.S. Pat. Nos. 3,684,052 and 4,384,174 to Sotome and Suzuki et al., respectively. An acoustical energy absorbing arrangement, on the other hand, is disclosed in U.S. Pat. No. 4,256,198 to Kawakami, et al. In all of such prior art arrangements, there is some energy absorption involved occasioned by the diversion of acoustical driving forces. Therefore, the extent to which sound reproduction quality may be improved in accordance with present theories is limited by physical contact or mechanical attachment, whether direct or indirect, between the frame structure of the loudspeaker and its radiating diaphragm. The problem is particularly acute for base speakers where the elimination of distortion is desirable.
The concept of supporting the gravitational loads of rotors by magnetic field suspension means is already known, as disclosed for example in my prior U.S. Pat. Nos. 3,761,148 and 3,794,391. The application of such magnetic suspension means for support of acoustical diaphragms was not, however, deemed to be a viable option under presently known theories in the acoustical arts. Thus, despite the crowded nature of the acoustical loudspeaker art, the elimination of all physical contact, connection or mechanical attachment between the frame structure and the diaphragm by magnetic means has not been considered, as evident from the disclosures in the more recent patents to Kawakami, et al. and Suzuki, et al., aforementioned.
It is therefore an important object of the present invention to provide a diaphragm supporting suspension system which is capable of improving acoustical reproduction quality beyond the limits inherent in presently known theories.
A further object in accordance with the foregoing object is to provide an improved diaphragm suspension arrangement that is most beneficial in eliminating distortion especially from a base speaker.